The heart of a computer is a magnetic disk drive which typically includes a rotating magnetic disk, a slider that has read and write heads, a suspension arm above the rotating disk and an actuator arm that swings the suspension arm to place the read and/or write heads over selected circular tracks on the rotating disk. The suspension arm biases the slider into contact with the surface of the disk when the disk is not rotating but, when the disk rotates, air is swirled by the rotating disk adjacent an air bearing surface (ABS) of the slider causing the slider to ride on an air bearing a slight distance from the surface of the rotating disk. When the slider rides on the air bearing the write and read heads are employed for writing magnetic impressions to and reading magnetic signal fields from the rotating disk. The read and write heads are connected to processing circuitry that operates according to a computer program to implement the writing and reading functions.
The continuing reduction of the bit size as magnetic recording densities are increased requires that the spacing between the sensor and the recording medium also be decreased. For example for 1 Tb/in2 the spacing should typically be 5 nm or less in order to attain the required signal to noise ratio (SNR). The presently-used carbon overcoat (COC) thickness needs to be reduced to 1 nm to satisfy this spacing requirement. Currently, there exists no viable alternative to reduce the thickness of current-art amorphous diamond-like-carbon (DLC) layers down to 1 nm thickness while maintaining the overcoat mechanical strength and its corrosion protection. At even higher areal densities, overcoat thickness down to the dimensions of a single atomic layer of carbon will be needed.